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Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document doesn't use any RFC 2119 keywords, yet seems to have RFC 2119 boilerplate text. -- The document date (February 22, 2021) is 446 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-05) exists of draft-irtf-panrg-path-properties-01 == Outdated reference: draft-irtf-panrg-questions has been published as RFC 9217 Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Path Aware Networking Research Group S. Zheng 3 Internet-Draft P. Liu 4 Intended status: Informational Z. Chen 5 Expires: August 26, 2021 China Mobile 6 February 22, 2021 8 Required path properties for applying path aware networking in 9 integrated space-terrestrial networks 10 draft-zheng-panrg-path-properties-istn-00 12 Abstract 14 Integrated space-terrestrial networks are heterogeneous networks with 15 various path characteristic, and usually belong to different 16 administrative domains. Therefore integrated space-terrestrial 17 networks can be seen as a use case of path-aware networking. This 18 memo introduces requirements on path properties when applying path- 19 aware-network in integrated space-terrestrial networks. 21 Requirements Language 23 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 24 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 25 document are to be interpreted as described in [RFC2119]. 27 Status of This Memo 29 This Internet-Draft is submitted in full conformance with the 30 provisions of BCP 78 and BCP 79. 32 Internet-Drafts are working documents of the Internet Engineering 33 Task Force (IETF). Note that other groups may also distribute 34 working documents as Internet-Drafts. The list of current Internet- 35 Drafts is at https://datatracker.ietf.org/drafts/current/. 37 Internet-Drafts are draft documents valid for a maximum of six months 38 and may be updated, replaced, or obsoleted by other documents at any 39 time. It is inappropriate to use Internet-Drafts as reference 40 material or to cite them other than as "work in progress." 42 This Internet-Draft will expire on August 26, 2021. 44 Copyright Notice 46 Copyright (c) 2021 IETF Trust and the persons identified as the 47 document authors. All rights reserved. 49 This document is subject to BCP 78 and the IETF Trust's Legal 50 Provisions Relating to IETF Documents 51 (https://trustee.ietf.org/license-info) in effect on the date of 52 publication of this document. Please review these documents 53 carefully, as they describe your rights and restrictions with respect 54 to this document. Code Components extracted from this document must 55 include Simplified BSD License text as described in Section 4.e of 56 the Trust Legal Provisions and are provided without warranty as 57 described in the Simplified BSD License. 59 Table of Contents 61 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 62 2. Terminology and Abbreviation . . . . . . . . . . . . . . . . 3 63 3. Path properties . . . . . . . . . . . . . . . . . . . . . . . 3 64 4. Fine granular properties . . . . . . . . . . . . . . . . . . 3 65 4.1. node properties . . . . . . . . . . . . . . . . . . . . . 4 66 4.2. Link properties . . . . . . . . . . . . . . . . . . . . . 4 67 5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 68 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 69 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 70 8. Normative References . . . . . . . . . . . . . . . . . . . . 6 71 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 73 1. Introduction 75 In the integrated space-terrestrial networks, endpoint is capable to 76 access space networks, mobile networks, and fixed networks. These 77 heterogeneous networks have essential difference on characteristics 78 and come from different service providers, which makes it difficult 79 to carry out unified management and control. Furthermore, different 80 with ground networks, the quality of links in space is fluctuating, 81 the network topology changes dynamically, and the resources of space 82 node is limited. It is necessary to come out a system to release the 83 burden of networks(especially space nodes with limited resource) and 84 leaving the complex function to endpoint. In other words, the path- 85 aware network may help to cope with the dynamics of this kind of 86 network. 88 According to the definition of [RFC5136], a path is a series of links 89 that connect a series of nodes from the source node to destination. 90 The properties of path can be seen from the overall point of view, or 91 decomposed into node properties and link properties. Corresponding 92 granular path awareness can be performed in the basis of the 93 capability of the endpoint and/or the required quality of service. 94 This memo will describe the required path properties from different 95 granularity in integrated space-terrestrial networks. 97 2. Terminology and Abbreviation 99 Integrated space-terrestrial Networks(ISTN): A network system that 100 comprehensively utilizes a variety of communication network 101 technologies including space networks and terrestrial networks to 102 achieve global coverage. The integrated system includes ground 103 segment and space segment. The ground segment includes terrestrial 104 network nodes such as ground stations, terminals, servers controllers 105 and terrestrial links such as cable, fiber. Space segment includes 106 space node such as satellites and space links such as laser and 107 radio. 109 3. Path properties 111 The path properties describe the overall properties of the whole path 112 from an end-to-end perspective. 114 Space and ground networks share some common properties, but due to 115 the essential differences between the space network and the 116 terrestrial network on characteristics such as mobility, link 117 stability, resources etc., some additional properties are required to 118 support path selection at the endpoint. 120 Common path properties 122 1. Properties in path 123 properties[I-D.irtf-panrg-path-properties],such as one way delay and 124 one way packet loss. 126 Additional path properties in space 128 1.Available time: path available time; due to the topological 129 dynamics of the space link, the path in the world-ground integrated 130 network is not always available. Therefore, it is necessary to set 131 an available time for each path; 133 4. Fine granular properties 135 In addition to the fluctuating latency, and bandwidth, the complex 136 space environment will lead to unpredictable wireless link 137 disconnection.The mobility of space nodes will lead to periodic 138 dynamic topology change. Therefore, the performance of the path 139 changes more frequently, and the fine granular properties can help 140 the integrated space-terrestrial networks to quickly locate 141 unpredictable faults and find the optimal alternative link instead of 142 discarding the entire path. For example, path properties can be 143 decomposed into node properties and link properties. 145 4.1. node properties 147 Common properties of nodes 149 1.Node computing resources: computing resources available on ground 150 nodes/space nodes. When the available computing resource is less, it 151 indicates that the node is heavy-loaded, and the path that contains 152 the node should be avoided when selecting a path. 154 2.Node storage resources: available storage resources of ground 155 nodes/space nodes. 157 Additional node properties in space 159 1.Node power: This is actually the most important property of space, 160 because the energy of satellite in space comes from solar panels, 161 which make the node energy fluctuating with time. If the power of 162 the satellite node is not sufficient to support additional computing/ 163 communication functions, the satellite node is not available; it can 164 be simply set to 0/1 to indicate whether the node supports additional 165 computing/communication functions. 167 2.Available interfaces of the node. The interface that can be used 168 to establish a link, it may contain a set of information indicating 169 the direction of interface and available next hop. This property can 170 be use to derive the topology information. The specific link status 171 is excluded and needs to query the link properties described below. 173 3.The future available interfaces of the node. The movement of 174 satellite nodes is periodic. Periodicity can be used to predict the 175 topology in the future to help make routing decisions. This property 176 can be sent in different manners, depending on the mechanism the 177 system used to deal with the network mobility. This property can be 178 sent in each time slot if the system use snapshot. Or to reduce the 179 interaction cost, event triggered property notification can be used, 180 that is the notification only executes when the available interfaces 181 changes due to unexpected event. 183 4.2. Link properties 185 Common link properties 187 1.Propagation delay:When a data packet propagates from the source 188 node to the destination node, the time required for the transmission 189 from the beginning to the end of the link is the propagation delay. 190 Data packets are propagated at the propagation rate of the link, and 191 its rate depends on the physical medium of the link. The propagation 192 delay is equal to the ratio of the distance between the nodes and the 193 propagation rate. As the distance between the nodes changes as space 194 node moves, the delay changes as well. 196 2.Link media: the link media can be laser/cable/radio etc., and the 197 different media can have different priority and cost, which should be 198 used to do the path selection decision. 200 3.Quality of link: This property can be indicated by bit error rate 201 or packet loss rate, depending on the network system. 203 Additional link properties in space 205 1. Available time: When the nodes at both ends of a link are 206 constantly moving relative to each other, the link may be unavailable 207 because the nodes move out of mutual visible area. Therefore, it is 208 necessary to know the available time of the link. 210 2. Link status: different from bit error rate, this property 211 indicates the state of link, for example, when the link is 212 temporarily unavailable due to space environment, it can be set in 213 leave and; when the link is unavailable due to mobility, it can be 214 set to down . The link state information may not come from space node 215 itself but from ground measurement and control station. 217 5. Summary 219 Integrated space-terrestrial Networks can take advantage of the PAN 220 and can be seen as a typical use cases. When PAN is introduced into 221 ISTN, it will have some different requirements on the path 222 properties, and this memo study the first question in 223 [I-D.irtf-panrg-questions] by list and explain some potential path 224 properties. 226 6. Security Considerations 228 It should be noticed that under the Integrated space-terrestrial 229 Networks background, the topology information comes from different 230 operators, they may not willing to expose their network information 231 to other operators or other 3rd parties, so it is crucial to find a 232 way to supply the information to end user while not expose to others. 234 7. IANA Considerations 236 This document has no requests to IANA. 238 8. Normative References 240 [I-D.irtf-panrg-path-properties] 241 Enghardt, T. and C. Krahenbuhl, "A Vocabulary of Path 242 Properties", draft-irtf-panrg-path-properties-01 (work in 243 progress), September 2020. 245 [I-D.irtf-panrg-questions] 246 Trammell, B., "Current Open Questions in Path Aware 247 Networking", draft-irtf-panrg-questions-08 (work in 248 progress), December 2020. 250 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 251 Requirement Levels", BCP 14, RFC 2119, 252 DOI 10.17487/RFC2119, March 1997, 253 . 255 [RFC5136] Chimento, P. and J. Ishac, "Defining Network Capacity", 256 RFC 5136, DOI 10.17487/RFC5136, February 2008, 257 . 259 Authors' Addresses 261 Shaowen Zheng 262 China Mobile 263 Beijing 100053 264 China 266 Email: zhengshaowen@chinamobile.com 268 Peng Liu 269 China Mobile 270 Beijing 100053 271 China 273 Email: liupengyjy@chinamobile.com 275 Danyang Chen 276 China Mobile 277 Beijing 100053 278 China 280 Email: chendanyang@chinamobile.com